Orbital device

ABSTRACT

An orbital device in which the orbiting outer member of a gerotor set is restrained from rotation but allowed to orbit about a plurality of circumferentially spaced bolts extending through a chamber in a housing by coaction between a like plurality of outwardly opening axially elongated grooves at the periphery of the outer member, the grooves being dimensioned to directly engage the bolts so as to restrict movement of the outer member to an orbital motion, the bolts being positioned inwardly of the axially extendant outer wall of the housing and the grooves in the outer member of the gerotor set being disposed radially outwardly of the crests of the internal teeth on the outer member.

oRBrrAL nevica BACKoRoUNDgoF THE INVENTION The prior art contains numerous examples of orbital devices in which a gerotor s'et is used in a fluid environment to serve asa motor or a pump. One such example may be seen inthe Huber U.S. Pat. No. 3,391,608, issued July 9,1968, for HYDRAULIC TOROUE MO TOR. In the Huber patent, a rotor having external teeth is disposed on a shaft and adapted to rotate inside the chamber of a housing and an outer member of the gerotor set is restricted to an orbital motion about the rotor and is utilized to effect a valving action of fluid to and from pockets ythat are formed progressively between the members so as to, in the case of a motor, cause rotation ofthe inner'rotor and a shaft upon which it is mounted and orbital motion of the outer member about its axis.

Other forms of restraining the motion of the outer member to an orbital path are shown, for example, in

the Waldorff U.S. Pat. No. 3,431 1969, for GUIDE MEANS.

In the Waldorff patent, the outer member of a gerotor set is provided with a pair of valve plates which overlap the inner member and which also -include grooves which are adapted to engage peripherally spaced rollers that are disposed on bolts extending through a chamber formed in a housing. Itis desired to maintain a line contact between the valve plates riveted to the outer member of the gerotor set and the rollers on the bolts.

SUMMARY OF THE INVENTION My invention is concerned with an improved orbital device in which the housing is comprised of but a few simple elements and in which efficient guiding of the outer orbital member of a gerotor set is accomplished through the use of radially outwardly opening grooves disposed radially outwardly of the crest of the internal teeth on the outer gerotor member and adapted to engage a like number of bolts extending through the housing adjacent the inner periphery of a cylindrical center sectionl of the housing that is of the same thickness as the gerotor set and which is of a continuous cross sectionwhich combine to provide the desired function of allowing orbital motion of the outer gerotor member while substantially eliminating distortion thereof and distortionof the chamber defined by the elements of the housing and leakage therebetween in the assembled orbital device.

These and other objects and advantages of my inven tion will become apparent from a consideration of the appended specification, claims and drawings in which:

,8-63, issued Mar. 1 l,

FIG. 1 is a top elevational view of an orbital device to which the principles of my invention may be applied A DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, an orbital device is indicated generally by reference character 10 and includes left and right ends 1l and 13 and a center sec tion 12 which are assembled to a mounting therefor indicated by `reference character L4. A shaft 15` extends inwardly of the housing defined by each of the last named elements and is rotatably joumalled therein. A pair of ports 16 and 17 are disposed on right and left end elements 13 and 1l, respectively, for connection to a suitable source of hydraulic fluid in a manner dependent upon the 'use to which orbital device 10 is going to be placed. Elements 11,412 and 13 are mounted to gether to form a unitary structure having an interiorly disposed chamber by a plurality of screw threaded members 18. A gerotor assembly comprised of'an inner rotor 20 having external teeth 21 and an outer member 23.having a plurality of internally extending teeth-24 are disposed in the chamber inside of orbital device l0 in the manner illustrated in FIG. 2 of the drawings. The outer periphery of `orbital member 23 includes a plu rality of radially outwardly opening grooves 25 and it may be noted that the'number of grooves is the same as the number of internal teeth disposed on outer orbital member 23 and that the-number of screw threaded fas# teners 18 corresponds to the number of grooves.

The gerotor set referred to above may be of the type disclosed in a certain copending application Ser. No. 321,237 filed Jan. 5, 1973 and assigned to the assignee of the present application in which the inner member of the gerotor set, rotor 20, is mounted upon and intended to rotate with a shaft, such as shaft 15 through suitable keys and the outer orbital member is utilized t to cooperate directly withlfluid ports disposed radially outwardly of the inner rotating member to effect a valving action of fluid to and fromchambers defined intermediate the internal and external teeth of the gerotor set so as to effect rotation of the inner member by the orbital motion of the outer member of the gerotor set.

`The location of grooves 25 radially outwardly of the crest of each of the internal teeth on orbital member 23 presents an element having a. substantially uniform thickness so as to avoid problems of distortion that would be present should the grooves be located elsewhere in the outer orbital member of the gerotor set.

It may also be noted that center element 12 is likewise of uniform thickness with respect to forces that may be exerted radially and thereby presents a maximum resistance to distortion due to such forces.

Having now therefore fully illustrated and described my invention, what I claim to be new and desire to protect by Letters Patent is:

l. In apparatus of the class above described including a housing comprised of a pair of end elements and a cylindrical center element to form a cylindrical chamber in which a gerotor set including an inner externally toothed element disposed on a shaft extending through the housing and an outer internally toothed orbital element, both disposed for movement within the chamber and valving therefor, the combination comprising; a radially outwardly opening groove disposed radially outwardly of the crest of each of the internal teeth on the outer element of the gerotor set so as to presenta substantially uniform radial wall thickness therefor; a like plurality of cylindrical elements extending axially of the chamber, said cylindrical elements being of smaller di- 'ameter than said grooves and being circumferentially equidistant lfrom one another, said cylindrical elements being engaged by said grooves to prevent 6. The apparatus of claim 5 in which the grooves have an arcuate extent of greater than 7. The apparatus of claim 5 in which the radius of the grooves is less than the radius of the internal teeth on the outer member.

8. The apparatus of claim 7 in which the grooves have an arcuate extent of greater than 180.

91. The vapparatus of claim 7 in which the center element of the housing is of uniform cross-section.

ik "F 1# 

1. In apparatus of the class above described including a housing comprised of a pair of end elements and a cylindrical center element to form a cylindrical chamber in which a gerotor set including an inner externally toothed element disposed on a shaft extending through the housing and an outer internally toothed orbital element, both disposed for movement within the chamber and valving therefor, the combination comprising; a radially outwardly opening groove disposed radially outwardly of the crest of each of the internal teeth on the outer element of the gerotor set so as to present a substantially uniform radial wall thickness therefor; a like plurality of cylindrical elements extending axially of the chamber, said cylindrical elements being of smaller diameter than said grooves and being circumferentially equidistant from one another, said cylindrical elements being engaged by said grooves to prevent rotation of said outer orbital element.
 2. The apparatus of claim 1 in which the center element of the housing is of uniform cross-section.
 3. The apparatus of claim 1 in which the grooves have an arcuate extent of greater than 180*.
 4. The apparatus of claim 3 in which the center element of the housing is of uniform cross-sectioN.
 5. The apparatus of claim 1 in which the grooves in the outer member are circular in cross-section.
 6. The apparatus of claim 5 in which the grooves have an arcuate extent of greater than 180*.
 7. The apparatus of claim 5 in which the radius of the grooves is less than the radius of the internal teeth on the outer member.
 8. The apparatus of claim 7 in which the grooves have an arcuate extent of greater than 180*.
 9. The apparatus of claim 7 in which the center element of the housing is of uniform cross-section. 